Congenital Disorders of Glycosylation are a diverse group of metabolic disorders presenting with a spectrum of clinical features ranging from severe neurologic manifestations and multisystemic involvement to hypoglycemia and severe gastrointestinal symptoms with normal development. There are now 17 types of CDG defined by distinct enzyme defects and genes all involved in the synthesis of N-linked oligosaccharides. The number of children and adults diagnosed with CDG in the United States is increasing rapidly with a wider variance in the phenotypes. It is clear that the clinical phenotypes and complications of these disorders are expanding. We are planning to include in these studies a new group of disorders called Congenital Muscular Dystophies(CMD). The underlying metabolic bases of these disorders is the abnormal synthesis of O-linked oligosaccharide of the mannose type. There are similar clinical questions in both of these disorders that can be answered as patient phenotypes are studied. The goal of the upcoming year will be to continue to identify and evaluate individual patients with CDG and CMD, to explore the clinical and biochemical features of untyped individuals and, through clinical research, continue to add to the compendium of clinical management strategies for physicians caring for these affected adults and children. We have completed an invited review in GeneReviews, an online resource for physicians caring for individuals with rare genetic disorders.